What is a alternator freewheel clutch?
You’ll typically find these on newer model vehicles, whilst older models will usually use traditional solid pulleys. The purpose of alternator freewheel clutches is to allow your alternator to freewheel when your car decelerates.
Is there a clutch on an alternator?
An Overrunning Alternator Pulley (OAP) has a one-way clutch mechanism inside the hub that allows the belt to turn the alternator in one direction, but allows the alternator to free-wheel and spin at its own speed when the engine suddenly decelerates.
Why do alternators have one-way clutches?
Should my alternator spin freely?
It should rotate smooth and free with no resistance or grinding. Should be free what’s the issue? Take it to the parts store and have it tested if you’re questioning it.
How do I know if my alternator has a clutch pulley?
A 99% test is to look at the pulley and see if there is a black, plastic cap on the end. Clutched pulleys will have a cap while un-clutched pulleys typically will not. On the alternator above the end of the pulley is covered by a black cap, thus it is a clutched-type pulley.
Should an alternator pulley spin both ways?
The pulley should be able to rotate in the counter-clockwise direction even though the cooling fins are being held in place. If the pulley DOES NOT rotate in the counter clockwise direct and it is locked to the rotation of the alternator shaft then it has failed and must be replaced.
Can you weld alternator clutch pulley?
Do not weld the overriding alternator clutch pulley….it’s there for a reason, and that reason is that the inertia of large alternators is by far the biggest inertia driven by the engine auxillary system, without the overriding clutch engine speed fluctuations are passed directly into the alternator, this places a lot …
How does an overrunning clutch work?
Overrunning clutches, sometimes called freewheel clutches, are used to freewheel in one direction while driving in another direction of rotation. When the driven shaft is rotating faster than the driveshaft, the clutch mechanically disconnects the driveshaft from the driven shaft. This engages the clutch.
How does a freewheeling alternator work on a car?
A freewheeling alternator has a clutch between the pulley and the alternator itself, meaning that when the battery is charged and there is a low electrical load there is a much lower braking torque on the belt.
What’s the difference between a clutch and an alternator pulley?
Clutched pulleys will have a cap while un-clutched pulleys typically will not. On the alternator above the end of the pulley is covered by a black cap, thus it is a clutched-type pulley. Outside of the possibility that the cap was removed and not replaced, this is a pretty reliable way to tell. How to test the alternator pulley.
How do you replace the alternator pulley on a VW?
Replacing the alternator pulley involves counter-holding the alternator shaft while loosening the pulley securing hut. This typically requires a special alternator pulley bit set which can vary between models. This Metalnerd Alternator Pulley Bit Set will cover all VW & Audi TDI models.
How can you tell if your alternator pulley has failed?
Signs of a failed alternator pulley. Outside of physically testing the alternator there are some things to watch out for that can signal the alternator pulley has failed. First, if your serpentine belt tensioner has failed, it is likely that the alternator pulley is faulty as well. Typically the failed pulley is the cause of the tensioner failure.